Evaluation of Natural and Surfactant-Modified Zeolites in the Removal of Cadmium from Aqueous Solutions

Abstract

The present study involves an investigation on the comparison of a Mexican clinoptilolite-heulandite zeolitic mineral and the modified zeolitic material with the surfactant hexadecyltrimethylammonium bromide (HDTMA) for the removal of cadmium from aqueous solutions. The effects of pH and contact time on the adsorption process were examined. The optimum pH for adsorption was found to be 7. Cadmium retention reached equilibrium in 32 h and the rate of cadmium adsorption by the zeolites was rapid in the first 10 h. Elovich's model best described the reaction rate. Batch adsorption experiments conducted at room temperature showed that the adsorption pattern followed the Langmuir -Freundlich isotherm model. The cadmium retention capacity decreased very slightly when the zeolite surface was modified with the surfactant HDTMA, and this material has advantages for its use in the removal of some other contaminants, such as anions and nonpolar organic compounds, like phenols. The results showed that natural zeolite and the surfactant modified zeolite could be considered as potential adsorbents for cadmium removal from aqueous solutions.

Removal of Cadmium By Natural and Surfactant-Modified Mexican Zeolitic Rocks in Fixed Bed Columns

“…According to previous studies (Cortés-Martínez et al 2004), the cadmium sorption capacities of natural and surfactant modified zeolitic rocks obtained from adsorption isotherms are similar, suggesting that the surface modification with HDTMA-Br does not affect significantly the sorption of this cation in batch systems. However, these capacities could be affected when the adsorbents are used in continuous systems due to the non equilibrium conditions present in the columns; besides, the results from batch systems can not provide accurate scale-up data required when designing effluent treatment systems which employ beds or columns.…”

“…The cadmium sorption capacity of the column packed with ZeNa (q b = 4.64mg/g) is lower than the maximum cadmium sorption capacity obtained from the isotherm for the same adsorbent (q o = 10.28mg/g), reported in a previous study (Cortés-Martínez et al 2004). The efficiency of the column was 45% approximately compared with the maximum capacity of the adsorbent to remove cadmium from aqueous solution in batch systems.…”

“…The efficiency of the column was 45% approximately compared with the maximum capacity of the adsorbent to remove cadmium from aqueous solution in batch systems. In batch processes, the equilibrium is reached approximately in 32h with the cadmium-ZeNa system (Cortés-Martínez et al 2004 whereas the residence time in the columns was much lower. Low et al (1999) explain that the adsorption in the column is not at equilibrium.…”

Cadmium Bioavailability, Uptake, Toxicity and Detoxification in Soil-Plant System

“…Iron oxides have a significant capacity to sorb and immobilize Cd (Liu et al 2014a, b). Thus, secondary Fe minerals formed by Fe(III) reducing bacteria and the Fe bacteriogenic oxides formed by Fe(II)-oxidizing microorganisms can reduce Cd bioavailability (Cortés-Martínez et al 2004;Muehe et al 2013), whereas the reduction of Cd bearing Fe(III) minerals by Fe(III)-reducing bacteria can increase Cd bioavailability (Muehe et al 2013). Different mechanisms have been proposed for the negative correlation between soil pH and Cd dissolution/desorption.…”

One Step Carbonization/Activation Process for Carbonaceous Material Preparation from Pecan Shells for Tartrazine Removal and Regeneration after Saturation

“…However some researchers have applied this model to solid-liquid sorption systems (Cortés-Martínez et al 2004). This model is represented by the following equation:…”